Medical imaging is a technology that has evolved substantially over the past few decades with an increasing diversity of modalities—Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Nuclear Medicine (NM) and Positron Emission Tomography (PET), to name but a few. Although the traditional notion of medical imaging involves the acquisition of a “static” image that captures the anatomy of an organ/region of the body, increasingly the use of more sophisticated imaging techniques allows dynamic studies to be made which provide a temporal sequence of images which may characterize physiological or pathophysiological information.
Dynamic medical imaging may involve the use of an imaging or contrast agent to increase selectively the contrast of a region in the image or to follow the uptake or flow in a region, so called bolus tracking. For example, one may inject into a patient a compound which has a biophysical, molecular, genetic or cellular affinity for a particular organ, disease, state or physiological process. Such contrast agents are selected to have a property that provides enhanced information to a given imaging modality by altering imaging conditions (normally by altering the contrast) to reflect the behavior of the compound in the body. The contrast agent will thereby move or change its distribution during dynamic medical imaging, and the optimal setting for the image acquisition will vary for consecutive acquisitions.
Also, dynamic medical imaging may require a patient to spend considerable time in an imaging device in order to acquire an image sequence. During this time, a patient may move due to natural bodily motion such as respiration, heartbeat, etc. This motion may corrupt the accuracy of the resulting images.
Furthermore, dynamic follow-up studies have to be done to monitor e.g. the changes of a pathology to determine its exact nature or its response to therapy. These follow-up studies may be taken days or weeks apart and require independent patient positioning. Changes in patient position and status between the follow-up studies may adversely affect the quality of the resulting images.
WO 04/080309 describes a device and method for adapting recording parameters in CT scanning using a pilot scan and static patient model. For imaging where dynamics is involved, the prior art provide techniques for motion correction after acquisition, see for example WO 00/57361. Such techniques do no provide means for improving the acquisition process of the dynamic imaging, only for correcting the acquired images.